Recently, a microwave has been applied to various application fields in addition to a wireless communication technology. For example, the microwave is applied as a local radio wave exposing unit which focuses a microwave onto a specific part in a human body to treat cancer or cause a significant reaction of a biological tissue. Current technologies which may be applied to such an application field include methods for focusing and illuminating radiation (for example, X-ray) having straightness or conducting an electric signal outside of a biological tissue, or radiating an electromagnetic signal over a broad part.
In the meantime, in order to focus an electromagnetic signal having diffraction or scattering characteristics, that is, a microwave onto a specific part in a biological tissue, a plurality of antennas is disposed outside the biological tissue and the microwave is focused through the antenna in accordance with a predetermined focusing method.
In this case, a method for precisely focusing a microwave onto a desired specific part of the biological tissue is required. Further, when a predetermined microwave is transmitted, it is also required to monitor whether the microwave is precisely focused onto a desired position. When the method is applied to a cancer treatment in the human body, if the microwave is focused on a normal tissue rather than a cancer tissue, the normal tissue may be damaged. Therefore, focusing accuracy is significantly important. Further, when the method is applied as a local radio wave exposing unit which causes a significant reaction of a biological tissue, in order to focus the microwave only onto a tissue of interest, the microwave needs to avoid being exposed onto other tissues. Therefore, the focusing accuracy is also important.